Method for processing steel tubes and the likes

ABSTRACT

A method for processing a steel tube includes the following steps: a softening step, in which a tube-to-be-processed is heated so that material property of the tube-to-be-processed is softened; a cooling step, in which the heated tube-to-be-processed is cooled down to a normal temperature; a wall cutting step, in which the cooled tube-to-be-processed is subjected to cutting by lathing an end section thereof so as to reduce wall thickness of the tube-to-be-processed at the end section; and a shrinking step, in which the thickness reduced section of the wall lathed tube-to-be-processed is subjected to compression to have an inner bore thereof shrunk and thus reduced, whereby occupation of the inner bore of the shrunk tube-to-be-processed by the wall thickness of the tube-to-be-processed is reduced so as to obtain a possible maximum inside diameter of the inner bore and prevent the tube-to-be-processed from undesired deformation and breaking.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to a method for processing steel tubes and the likes, and more particularly to a steel tube processing method that allows a steel tube to present a possibly maximum inside diameter after being processed for shrinkage and also prevent the processed steel tube from undesired deformation and breaking during the process of tube shrinkage.

DESCRIPTION OF THE PRIOR ART

Taiwan Patent Publication No. 302309 discloses a square steel tube manufacturing method and a round steel tube manufacturing method, wherein a steel tube is heated in a heating oven and the heated steel tube is subjected to hot forging by a steel tube shaping mill. The so processed steel round tube is then cooled down. Although the round steel tube has been subjected to heating to change the material property of the round steel tube, no lathing has been applied to partially remove the wall thickness of the round tube, whereby when the round steel tube is processed by shrinkage of diameter, as shown in FIG. 1 of the attached drawings, the diameter-shrunk round steel tube, which is generally designated at 1, has a wall thickness d2 that is substantially the same as the wall thickness d1 of the round steel tube 1 before the tube is subjected to diameter shrinkage. Consequently, after the shrinkage of the round steel tube 1, the thickness d2 undesirably occupies the inside diameter of the inner bore 11 of the round steel tube 1. This might excessively reduces the inner bore 11 of the round steel tube 1 and thus imposes undesired constraint to the inner bore. Further, since the wall thickness d2 of the diameter-shrunk round steel tube 1 is substantially the same as the wall thickness d1 of the round steel tube 1 before shrinkage, the shrinkage operation may cause undesired deformation or breaking of the round steel tube 1 during the process of shrinkage. Thus, it is desired to provide further improvement in this respect.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a method for processing a steel tube and the likes. The method comprises the following steps:

a softening step, in which a tube-to-be-processed is heated so that material property of the tube-to-be-processed is softened;

a cooling step, in which the heated tube-to-be-processed is cooled down to a normal temperature;

a wall cutting step, in which the cooled tube-to-be-processed is subjected to cutting by lathing an end section thereof so as to reduce wall thickness of the tube-to-be-processed at the end section; and

a shrinking step, in which the thickness reduced section of the lathed tube-to-be-processed is subjected to compression to have an inner bore thereof shrunk and thus reduced, whereby occupation of the inner bore of the shrunk tube-to-be-processed by the wall thickness of the tube-to-be-processed is reduced so as to obtain a possible maximum inside diameter of the inner bore and prevent the tube-to-be-processed from undesired deformation and breaking.

The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.

Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a conventional round steel tube.

FIG. 2 is a flow chart showing a method for processing steel tubes and the likes according to the present invention.

FIG. 3 is a cross-sectional view showing a tube-to-be-processed according to the present invention with wall thickness thereof being partially removed.

FIG. 4 is a schematic view showing the tube-to-be-processed according to the present invention demonstrating an end of the tube forcibly bent.

FIG. 5 is a schematic view illustrating the possible maximum inside diameter that can be obtained in a tube-to-be-processed according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.

Referring to FIG. 2, a method for processing steel tubes and the likes according to the present invention comprises the following steps:

a softening step (reference numeral 2), in which a tube-to-be-processed is heated so that material property of the tube-to-be-processed is softened, internal stresses are eliminated, and elastic modulus is softened, the heating being carried out at a temperature in the range of 800-1,200° C.;

a cooling step (reference numeral 3), in which the heated tube-to-be-processed is cooled down naturally at a cooling temperature of normal temperature, namely room temperature, so that the tube-to-be-processed 6 restores original mechanical property to facilitate lathing operation;

a wall cutting step (reference numeral 4), in which, as shown in FIG. 3, the cooled tube-to-be-processed 6 is subjected to cutting by lathing an end section thereof so as to reduce wall thickness 65 of the tube-to-be-processed 6 at the end section, a difference being consequently present between a lathed outside diameter 63 and an original outside diameter 62, and wherein due to the original wall thickness 61 is different from the lathed wall thickness 65, the end of the tube-to-be-processed 6 shows flexibility 66 as being forcibly bent, as shown in FIG. 4; and

a shrinking step (reference numeral 5), in which the thickness reduced section of the wall lathed tube-to-be-processed 6 is subjected to compression to have the lathed wall thickness 65 of the tube-to-be-processed 6 inwardly compressed and an inner bore thereof shrunk and thus reduced, so that the tube-to-be-processed 6 shows a possible maximum inside diameter 64 of the inner bore thereof, as shown in FIG. 5, which reduces the resistance against passage of an object contained inside the tube and thus allows for smooth passage of the object.

By heating and softening the tube-to-be-processed 6, the material property of the tube-to-be-processed 6 is destructed, internal stresses are eliminated, and the elastic modulus is softened, whereby the tube-to-be-processed 6 is prevented from undesired deformation and breaking caused by forcible compression during the process of shrinkage. By means of partially lathing the wall thickness of the tube-to-be-processed 6 to thin the lathed wall thickness 65, the tube-to-be-processed 6 can present a possible maximum inside diameter 64 after the shrinkage operation, as shown in FIG. 5. By applying the above discussed steps to shrink the tube-to-be-processed 6, the occupation of the inner bore 64 of the shrunk tube-to-be-processed 6 by the wall thickness 65 of the tube-to-be-processed is reduced so as to obtain a possible maximum inside diameter 64 of the inner bore and prevent the tube-to-be-processed 6 from undesired deformation and breaking.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 

1. A method for processing a steel tube, comprising the following steps: a softening step, in which a tube-to-be-processed is heated so that material property of the tube-to-be-processed is softened; a cooling step, in which the heated tube-to-be-processed is cooled down to a cooled temperature; a wall cutting step, in which the cooled tube-to-be-processed is subjected to cutting by lathing an end section thereof so as to reduce wall thickness of the tube-to-be-processed at the end section; and a shrinking step, in which the thickness reduced section of the wall lathed tube-to-be-processed is subjected to compression to have an inner bore thereof shrunk and thus reduced.
 2. The method according to claim 1, wherein the tube-to-be-processed is heated to a temperature in a range of 800-1,200° C.
 3. The method according to claim 1, wherein the cooled temperature to which the heated tube-to-be-processed is cooled down is room temperature. 